Corrugated paper machine



June 15, 1954 P. BROWN CORRUGATED PAPER MACHINE Filed Nov. 3, 1951 4 Sheets-Sheet l INVENTOR RwL BROWN Zwml Mfif Y pmwqd/ ATTORNEY June 15, 1954 P. BROWN 2,680,996

CORRUGATED PAPER MACHINE Filed Nov. 3 1951 4 Sheets-Sheet 2 INVENTOR. PA UL 8R0 w/v June 15, 1954 P. BROWN 2,680,996

CORRUGATED PAPER MACHINE IN V EN TOR. Pau/ ,Zroza)? ATTORN June 15, 1954 P. BROWN 2,680,996

CORRUGATED PAPER MACHINE Filed Nov. 3, 1951 4 Sheets-Sheet 4 1 VENTOR. Pazl/ gram AT TORNEYS Patented June 15, 1954 UNITED STATES PATENT OFFICE CORRUGATED PAPER MACHINE Paul Brown, Walpole, N. H., assignor toPacka-ging Materials Com, Providence, B. La corporation of Rhode Island Application November 3, 1951, Serial No. 254,691

12 Claims. 92-39) This invention relates to machines for molding corrugated paper board.

The invention has for its object to provide certain improvements applicable to machines of the type generally disclosed in U. S. Letters Patent No. 2,221,200 to Eugene L. Perry, by virtue of which improvements a molded corrugated board may be fabricated at a much higher rate of production than obtainablewith the machine of the Perry patent.

A further object of the invention is to provide a machine of the character described in the above-mentioned patent on which corrugated board having different characteristics of stifiness and density may be manufactured by making certain simple adjustments of the machine.

A further object of the invention is to provide an improved machine of the character described wherein a much greater percentage of the water in the pulp is extracted before drying than in machines as heretofore constructed without unduly increasing the density of the fiber, whereby the manufacturing cost of the molded sheet is greatly reduced.

Another object of the invention is to provide a machine which will produce at a lower cost than heretofore corrugated board having a backing sheet adhesively secured thereto.

Further objects of the invention will appear from the following specification and drawings, wherein Fig. 1 is a diagrammatic sectional view through the cylinder of the machine on a plane transverse to its axis of rotation, showing a preferred arrangement of the several elements;

Fig. 2 is an enlarged sectional detail of the cylinder wall and one of the press rollers shown in Fig. l

Fig. 3 is a similar View showing an additional press roller which is used in making one type of board;

Fig. 4 is a sectional view similar to Fig. 3 but showing a modified form of the parts therein disclosed;

Fig. 5 is a detail sectional View on line 55 of Fig. 4;

Fig. 6 is a plan view on a much enlarged scale of a portion of the cylinder wall;

Fig. '7 is a diagrammatic View showing the arrangement of the apparatus for drying the corrugated board and securing thereto by adhesive one or more backingsheets;

Fig. 8 is andiagrammatic view of a modified form of the mechanism for applying backing sheets;

Fig. 9 is a fragmentary perspective showing a modification of the adhesive applying mechanism;

Fig. 9a shows another modification;

Fig. 10 is a diagrammatic View of another modification for applying a single backing sheet and also creasing the ribsof the corrugated sheet;

Fig. 11 is a detail ofpne formof creasing roller;

Fig. 12 is a similar detail showin another form of creasing roller;

Fig. 13 isv a fragmentary view showing the creasing producedby. the. rollerof Fig. 11; and

Fig. 14 is a similar View showing the creasing producedby the roller of Fig. 12.

Referring to the drawings, l indicates the cylinder upon which the corrugated board is molded, the cylinder having grooves 2 corresponding to the position of the ribs in the molded sheet, and grooves 2 being separated by parallel ridges. The. grooves .are preferably of substantially rectangular cross section and at intervals along the bottom of the grooves, holes 3 are provided leading to the interior of the cylinder.

A flow box l of any suitable design is mounted adjacent the path of the cylinder at a location above the plane of the horizontal axis of the cylinder and to one side of the vertical axial plane of the cylinder on the side of the cylinder where the surface of the cylinder is moving up wardly. Within the cylinder is a suction box 6, the edges of which are provided in thenusual manner with packing contacting the inner surface of the cylinder, whereby pulp will be drawn into the grooves 2 and against the face of the cylinder and a substantial portion of the water in the pulp willbe withdrawn through the perforations in the bottom of the grooves during the passage of that portion of the drum wall overthe suction-box.

Suction box 6 is divided into a plurality of chambers Ea; 6b, 6c and 6d, each having a separate connection tea suitable vacuum pump or other source of suction. The chambers are divided'from one another by walls also provided with packing contacting the inner surface of the cylinder I so that different degrees of vacuum can be maintained in 'the different chambers. Chamber 6a surrounds an area which is opposite flow box '3 and the degree of vacuum maintained in this chamber is the lowest inasmuch as the pulp at this stage is still in liquid suspension and too high a vacuum would cause substantial amounts ofpulp to bedrawn through with the water. A considerably higher vacuum is maintained in chambers 5b, 5c and Ed.

The surface of the drum containing the corrugations is covered with one or more sheets of foraminous material such as wire screening. The screening is not shown in Fig. 1 because of the small scale of that figure, but it will be understood that the screening covers the entire corrugated surface of the drum, and preferably two sheets of screening are used. The construction and arrangement of the screens is shown in Figs. 2, 3, 4, and 6. The under sheet I is of comparatively coarse mesh, while the outer layer 8 of screening is of comparatively fine mesh. The layers of screening are corrugated so that the outer surface of the screen 8 corresponds to the desired contour of the face of the finished corrugated paper containing recesses in which the ribs of the corrugated paper are molded. In

order to facilitate the proper draining of water from the pulp and also to adequately draw the pulp into the recesses or grooves in the wire screening which overlies the grooves 2 in the surface of the cylinder, the grooves in the cylinder and those in the screens are of different contour. Thus, the grooves in the cylinder are of rectangular cross section, while the grooves in the screens are of a different size and shape, for example, of semicircular cross section, as shown in Fig. 2. As here shown, the crowns of the ribs on the under side of the screening contact the bottoms of the respective grooves 2 along the middle line thereof, leaving spaces in the corners of each angular groove to provide an unimpeded passage for the water squeezed and drawn out of the pulp in its passage through the machine, while at the same time providing ample support for the screening.

I also preferably provide a series of press rollers contacting the pulp at it moves with the cylinder from the flow box to the endless conveyor 9 by which the sheet of molded pulp is removed from the drum. In starting up, an air blast device I0 is employed to blow the end of the web of pulp of the cylinder.

The first roller I! of this series is preferably a rubber covered roll, the rubber being fairly soft and having a smooth surface. The roller i I is mounted in spring pressed bearings, such as shown at if, having provisions for adjusting the a spring pressure. The pulp on the cylinder as it approaches the press roller H has been but loosely compacted by the suction, as shown at the left of Fig. 2, and contains a high percentage of water. As the pulp passes under the roller H the pulp is compressed and a large portion of the entrained water is expressed through the screens and drawn into the suction box. After passing the roller H the layer of pulp expands considerably as indicated at the right of Fig. 2.

The pulp is again compressed with the extraction of more water before the board reaches the conveyer 9. In Fig. 1 I have shown a ribbed press roller 13 arranged over the cylinder I beyond the roller II. This roller [3 is not necessarily used for making the soft flexible packing sheets for which the board is principally used but only for board having greatly increased fiber in both ribs and intermediate portions, such as described in my co-pending application filed concurrently herewith. In making the soft board the roller [3 may be omitted and the advancing cylinder carries the pulp layer from the roller II to a second roller of the same construction and arrangement as the roller H, positioned as shown 4 at [5 in Fig. 1. The roller l5 overlies a later suction chamber and on passing under the roller [5 over this suction chamber, the pulp is further compressed and more water is expressed from it and carried away by the suction.

The spring pressure on the rollers H and I5 and the suction maintained in the suction chambers 6b, 6c and 6d are so adjusted that the water-solids ratio of the pulp is altered from in the order of 995-5 to 78-22. With the water content so reduced the paper board is self-sustaining and is easily removed from the cylinder by the conveyor 9. The large water removal by the rollers l l and I5 and the suction chambers without unduly compacting the pulp is largely due to the screen construction above described which permits a free withdrawal of the water as it is expressed from the paper.

Any wet pulp or liquid material that flows down the inside of cylinder l below the flow box 4 is removed by means of a trough 16 having a doctor blade l1 and an outlet Iii. The water left in the pulp as it leaves the cylinder must be removed by evaporation. By machines as previously constructed the best water-pulp ratio heretofore obtainable was approximately 83-17. The finished board has about 8% to 10% moisture content and the reduction in the amount of water which has to be evaporated for each ton of paper is reduced by about a ton and a half by the use of the new machine.

For making board such as disclosed in my copending application of even date herewith entitled Packaging Materials, Serial No. 254,692, the second roller I3 is used preferably in addition to the smooth-faced roller l I. Also, preferably I fiow a deeper or thicker pulp from sluice box 4. This is indicated by the depth of the pulp P, as it approaches roller I3 after leaving roller H (Fig. 3). Roller I3 is provided with ribs 13 positioned to register in timed relation with the grooves 2 in the cylinder as the cylinder and press rollers are rotated. In the form shown in Fig. 3 ribs 13 are of substantially semicircular cross section, and the bearings of roller I3 which are adjustable as shown, are set so that the surface of the rib is spaced from the surface of the groove in the fine mesh screen a which covers the grooves 2 of the cylinder, about the same distance at the middle of the grooves as along the sides.

By this construction the pulp in the grooves which has been picked up during the passage of the cylinder past the sluice box will be compressed by the passage of the drum under roller 13, and the whole sheet will be reduced to a definite thickness which bears a relation to the thickness of the finished sheet. However, since the pulp is by nature quite resilient, as soon as it passes roller i3 it springs back to a considerable extent as indicated at the right of roller H3 in Fig. 3. Hence, the effect of roller [3 is not to produce highly compressed fiber in the ribs of the finished sheet but the combined effect of flowing a thicker mass of pulp onto cylinder l and the use of the ribbed roller i3, is to put more fiber into the ribs formed in the grooves in the wire mesh 8 than in the intervening portions, or what appears on the opposite side of the finished sheet as low, fiat-topped ribs. In this way, the structure of the ribs formed in the channels of the fine mesh 3 is rendered denser than the fiber in the opposite, flat-topped ribs, thus substantiall increasing the strength and rigidity of the finished sheet. There being more fiber in the rounded ribs than in the opposite, fiat-topped ribs, or intervening portions; the compressing effect of ribbed rollerv ES -is torenderthe fiber in these rounded-ribs more dense than'the'fiber in the intervening portions.-

The press roller m is preferably positively driven by gearing, not shown, in synchronism, with the cylinder i. That is to say; the roll and the cylinder have the same peripheral speed, so that the ribs on roller !3 will properly register. with the corrugations in the surface of the cylin der but will at thesame time'be maintained at asuitable distance outoi contact with the. surface of the cylinder.

The ribbed rollerl3: may also he positionedtat a point overone of the suction chambers 6b. or- 60; but'it is preferable to arrange these chambers asshown, that is, withxonessuction chamber. to on one'side of thepoint of contact between he ribbed roller 60 whollytothe other side, so that there will be. no likelihood of the suction disturbing: the distribution of the pulp in the grooves ofthe: cylinder during the pulp-compressing op eration.

In making'this board, I also preferably use the third roll beyondthe ribbed roller" 53. The suction chamber do which underlies the roller serves to extract from the pulpzthe'water expressed by the rollers itzand' l 5;

The improved corrugated board as disclosed in my above mentionedcopending application may also'bemade by flowing-a still'thicker: or deeper pulp, that is, somedeeper than indicated at P in Fig; 3, from-thesluice box and with the use of one ormore of. the smooth press rollers I I, that is; withoutiemployingthevribbed roller 53. The difierence in the density of the fibers in the ribs and1in the. intermediate portions of the board will not .be as-great, however, as when roller- 63 isxused, and-the percentagerofmoisture will be higher.

The boardformed on'tne machine as above describedhasexceptionaltear resistance and arelatively stiff board, particularly; in the direc tionzofithercorrugations, because ofthe increased fiber content both in the ribs andthe intermediateiportions, and? when sheets so made are providedwith backing sheets, as shown and described ins-mycopendingsapplication filed contemporanecuslyherewith, a strong, rigid, corrugated boardis: formed which .is particularlysuitable for the manufacture or packing cases and the like;as well as'slight Weight-boxeaall as fully described in my said co-pending application;

In Figs; 4 and-5 I have-shown amodified-con-v struction for producing sheets havingcorruga-- tions'of trapezoidal crosssectionas disclosedin Patent No. 2,48%,047 to Eugene L. Perry; As here shown,- the grooves in'the coarse screen I and fine screen 3 forming the. surface covering of the cylinder l-. are of trapezoidal c-rosssection, while the underlying groovesi are of rectangular cross section tothereby leavefree spaces inthe corners of the grooves for the reception of water asit is drawn out or" the pulp by thesuction in the box 5 and pressed out by the rolls 5 l and 55. In order to facilitate tl e'drainage cfwaterfrom the grooves 2; shallow grooves 2b may be provided on each side of the'holes' 3 leading into the open corner spaces of the grooves 2 Between the'heles 3 the bottom face' of the groove 2 is fiat and forms a solid'support for the contacting outer surfacesof the ribs'in the'screens 1 and '8 which are-seated in the-grooves 2.

A press roll 13d of the sameconstruction as thepreviouslyidescribedpress :roll El 3; but Lwithtrapee I surface'contour. In Fig. 4 1. have shownsuch aroll as used inmaking'a'sheet with trapezoidal ribs. The bearings of-the roll are so. adjusted as to compress the fiberinthegrooves ofitnev cylin-. der in about the same manner as. previously described in connectionwith roll IS.

The ribbed roll lSainsures. the. formation in the back'oi the sheet of shallow grooves underlying the moldedribson the opposite: side of the. sheet in the same'way as roller i3; Such'grooves will usually b'eiormedin the surface of thesheet by suction atone,- but it is desirable. to provide a: press roller in order that the ribs be uniform throughout the sheet! The machine-hereindisclosed isemployed for manufacturing the corrugated sheet used in. making the packing sheet of my co-pending' application Serial No. 218,31 i filed March 3O,

1951, now-Patent No. 2,6214%; The roll I3 -znay be removed altogether in the manufacture of such sheets, butit is preferable to use the roll lo? adjusted to lightly compress the sheet in order" that variations in the consistency of the pulp and in the suction maintained in the suction boxes will not alterthe thickness of thesheet.

It has been mentioned previously that the water left in thepulp as it leaves the cylinder must be removed by evaporation. This is'accomplishedby the drying apparatus illustrated diagrammatically in the upper portion ofFig. '7. It comprises two endless conveyors arranged within a suitable housing. One of these conveyers is the conveyer 9"previouslyreferred to and the second conveyer is indicated by reference numeral El and is arranged parallel to and somewhat below conveyer 9, the two conveyersbeing of approximately; the same length. The elongated housing 22*is of sheet metal appropriately insulated to conserve heat and provided with a sufficient number of heaters 23 with automatic control to maintain the air within housing 2.2"at the desired temperature.

Blowers 24 are also provided to circulate the heated air-within the housing to bring it repeatedly intobontacttrith the traveling web of pulp, todraw inthe desired amount of fresh air' and to cause the moisture-laden air to be discharged; forexample, through one or more outlets, such as-indicatedat 25: It will be understood that the; pulp web leaving-molding cylinder I is takenbr; the upper surface of conveyer 9 and carried to; the right to the end of-the drying chamber where the-web leaves this con'veyer and descends onto the upper portion of the lowerconveyer 21;

HousingZiand theconveyers 9 and 2! are of such length andso. coordinated as to conveyer speed, air temperature, etc., that "the pulp web or corrugatedboardzfi will besubstantially dry when itleaveszthe chamber at the left as shown in Fig. 7.] In atypical installation the length'of housing 22 is from: to feet. It will be understood that chamber 22 is a wholly closed structure except at the points of introduction-and discharge of thepulp web;

Eitherthe soft type of corrugated board, which isproduced by flowing a pulp of moderate thick-- ness iromthe sluice box 4 and without the use oi-pressrolls l3'or l3'a, orthe harder typeof: corrugated board, which is. produced by flowing a: thicker-pulp :fromzthe; sluice box; orby: the use,

of the corrugated press rolls l3 or1|3a.;. or by;

both flowing a thicker pulpand using these press rolls, may be provided with a backing sheet on one or both sides. A backing sheet of comparatively lightweight kraft paper is usually applied to one side only of the soft type of corrugated board to form a cushioned wrapping paper, a new product more fully described in my co-pending application entitled Cushioned Wrapping Material filed of even date herewith, and which may be employed in stores, etc., like any other wrapping paper where it is desired to protect glassware or other fragile goods.

The harder type of corrugated board has a somewhat thicker sheet of kraft paper applied to it on both sides for the purpose of making a corrugated paper product which is suitable for use in making shipping cases for heavy articles, and only one backing sheet for lightweight boxes.

Corrugated board for these purposes can be made by the apparatus of this invention at less cost than the corrugated board which is customarily employed in making shipping cases and cartons due to the fact that the complete corrugated board is produced in one continuous operation. That is to say, the corrugated web passes from the molding machine, to the drying apparatus to remove the excess moisture, and thence to the laminating apparatus by which a backing sheet is applied to one or both surfaces of the corrugated web, and the finished product is cut up into sheets of commercial dimensions, or wound upon a take-up roller; The material moves forward without stopping from the time that the pulp is flowed onto the drum of the molding apparatus until it is delivered in finished condition. The dry web 26 emerging from the lower left end of the drying housing 22 preferably is carried between a series of tension or guide rollers 21. The lowermost roll 2'! serves to direct the web 26 to the laminating apparatus.

This is shown in Fig. '7, lower part, and may be of conventional construction comprising upper and lower endless pressing belts 28, the lower belt being shorter and providing space ahead of it for heaters accelerate drying. An upper backing web 30 of kraft paper of suitable weight and a lower backing web 3| of similar paper and usually of the same weight are drawn between the pressure belts which cause the backing webs to adhere to the opposite faces of the board 26 by means of previously applied adhesive. Suitable adhesive, such as sodium silicate, may be applied to either the corrugated web 26 or to webs 30 and 3|.

Web 30 comes from a magazine roll 32 and passes over an adhesive applying roller 33, whereas adhesive is applied to the lower side of corrugated web 26 by an adhesive roller 3311. Web 3| is from a magazine roll 34 and passes over a heated roller 35 and thence over a pressing roller 35 below the front end of upper belt 28. Regardless of the manner of applying the adhesive and whether one or two backing sheets are applied to board 26 the completed laminated corrugated web 44 is carried to the right to a cutting knife 45 arranged to cut it into sections of any desired length.

Referring to 8, the arrangement here is such that the web of corrugated board 26 receives the adhesive on both upper and lower sides. Web 26 passes in contact with a lower adhesive roller 31 which applies the adhesive to the bottom of the web, and with an upper adhesive roller 38 which applies the adhesive to the top of web 26.

29 to heat the assembled layers and It will be understood that if it is desired not to apply any backing sheet to the web 26, the laminating mechanism may be omitted and the web passed directly to a take-up roll (not shown).

Figs. 9 and 9a show two ways of applying the adhesive in spaced and limited areas to make the cushioned wrapping material referred to above. In Fig. 9 the adhesive is applied in spots 39 to one of the backing sheets, for example, the upper backing sheet 46 (Fig. 10), only one backing sheet being used. These spots are distributed uniformly over the surface of sheet 46, being considerably separated and of comparatively small size. The purpose is to provide a cushioned wrapping material of much greater flexibility than if the adhesive were applied throughout the entire area of the backing sheet, all as set forth more particularly in my copending application above mentioned. The adhesive may be applied in this manner by any suitable mechanism such, for example, as the roller 48 which is provided with projections 4| suitably arranged to print the spots 39 of adhesive on the web as the web passes between roller 40 and press roller 42. It will be understood that the adhesive is received by projections 4| from an adhesive transfer roller 43.

The adhesive may also be applied in stripes instead of in spots, with the stripes running crosswise of the ribs and lengthwise of the corrugated board. In fact this is the preferred method of application, and an adhesive roll 49a is shown in Fig. 9:1 for applying the adhesive in a series of stripes 39a formed by the circular ribs lla. Roll 40 or roll 49a may be arranged to apply the adhesive either to web 30a as shown in Fig. 10 or to the corrugated web in a manner somewhat similar to the showing of Fig. 8. Although the single web of backing material 46 may be applied to a web of the type shown at 26 in the previous figures, wherein the ribs on opposite sides of the sheet are of about the same size, it is preferable to employ for the cushioned wrapping material a web such as indicated by numeral 41. Web 41 is molded in exactly the same manner as web 26 but is provided with a series of rounded ribs 43 on one surface of comparatively thick molded fiber connected by intermediate portions 49 which appear on the opposite side as relatively fiat and thinner ribs.

The spots of adhesive may be applied to these portions 49 at intervals by roll 46, and Fig. 10 is intended to indicate that spots 39 have a spacing substantially equal to a multiple of the ribs 48, that is, a row of adhesive spots is applied across the sheet on, for example, every second connecting portion 49. It will be understood that the spacing of the adhesive spots 39 laterally is preferably about the same as the longitudinal spacing just described. The spacing and size of the spots 39 or the stripes 39a may be varied considerably.

As the laminated material issues from the right-hand end. of the laminating apparatus it passes between a creasing roller 59 and a cooperating presser roll 5!, and then is drawn onto a take-up roll 58. Creasing roller 50 is provided with a series of circular knives 52 (Fig. 11) which are spaced apart lengthwise of the roller. These knives are suitably constructed to press indentations 53 (Fig. 14) in the lower surfaces of ribs 48 to facilitate the bending of the material in a direction lengthwise of the ribs, as more :means of'the molded web El, which is made from 1 used pulp. By applying the web 35 in the "manner describedso-that" the web is not cause'd to -adhere throughout its entire surface to the oorrugated web ll-but only in limitedandspaced areas as indicated, combined with-thecreasing Jof the'ribs 48 of the corrugatedsheet, awrapping: material is provioled which can readily be folded aroundfragile articles such asglasswa're, and at the same time affords a cushioning'protection which has proved extremely etfective'i-n preventing breakage.

By the apparatus of thepresent invention varinus products mentioned, namely-the double-faced corrugated board, the -single-ia'ced corrugated board; the cushioned wrapping material and the corrugated sheet or board, 2$ or t? by itself, all'can be producedin one continuous operation. Thatis to the pulp is flowed-continuously -onto the molding r cylinder i, which is rotated continuously at uniform speed. Conveyorsd and 1 2i of the dryingapparatus'QZ-are also operated continuouslyand at the same uniform speed --as the surface speed of cylinder i. The endless presserbelts'it of the laminator, as-well -as the scoring-or creasing rolls 5?, M are also operated #at' 'this same speed. 7

The pulp passes directly frommolding cylinder t-othe drying chamber 22 andthence directly to the laminator andto the scoring rolls if these are'used. 'The motionof the-pulp web'is'continuous from the time it is first formed until'the complete -product is delivered fromthecutting knives "45 or onto the take-up roll 58, or the like. Hence, the '-apparatus embodies not only the advantages of continuous. production as'dis- 'tinguished from batchproduction, but 'also the advantages resulting from producing the: com- ,apleteproduct in one continuous operation-in- :stead of in a series of separates'teps.

It -will-be understoodthatvarious changes in the arrangement and details of the'apparatus "-may'ioe made without exceeding the scope cf-the invention which is defined in the appended claims.

I claim:

1. .ln machine for molding corrugatedpaper beard the combination of a molding cylinder having .agrooved outer surface, means for ap- ..plying a layerof paperpulp to said surface with said grooves --substantiallynlled with pulp, holes in the cylinder wall within said grooves for the extraction of water fromthe pulp, andaroll having *ribs "thereon corresponding with the grooves of the cylinder and means for maintaining said roll with the surface of its ribs spaced from the surface of the grooves by a definite distance whereby the pulp in said grooves is pressed to a definite thickness.

2. In a machine for molding corrugated paper board the combination of a molding cylinder ,having --a--;grooved outer surface, means for aptplyi-ng-a continuous layer-of paper pulp to said surface withsa-id.groovessubstantially filled. with --pulp, holes in 'the cylinder wall within said :grooves :for the extraction "of -water from the pulp; and aroll having: ribsthereon of aheight substantially equal to the depth of saidgrooves and means for maintaining said-rollwith its suriace-spacedfrom thesurfaceof the cylinder by :a distance substantially equal to the layer of ramp on the=surfaceof the cylinder-between said grooves.

3. In a machinefor molding corrugated paper board the combination of a moldingcylinder -.aving=a-grooved outer surface, meansfor-applying a layer of paper pulp to said "surface with said grooves substantially-filled with-pulp,--ho1es in the cylinder wall along the bottoms of said 'gro'oves'ior-the extraction of waterfromthe-pulp, "and means for pressingsaid pulp comprising-a roll having ribs thereorr corresponding with the grooves of the cylinder and means for maintain- "ing saidrollwith its surface'spaced a definite distance from thesurface of the cylindena second press roll of cylindrical contour, and yielding 'means for maintaining said-roll in contact-with the pulpon-the surface of said cylinder.

4. In a machine for molding corrugated paper board :the combination of "a molding cylinder having a grooved-outer surface, "means for-applying-a layer'ofpape'r pulp to said surface with --said grooves substantially filled with pulp, holes in the cylinder wall along the bottoms of said grooves for-the extraction of water from the pulp, and means for .pressing said Jpulp comprising a roll having ribs thereon corresponding with the grooves'of' the cylinder and means for maintaining'said roll with'its surface 'spaced'a definite distanceirom the surface of-the cylinder,- at second: press roll of cylindricarcontour andasuc- *tion box;positioned within said cylinder underlying said second roll.

5. In a'machine for molding corrugated paper boa'rd the combination "of I a cylinder having a grooved outer-surface, means for applyinga layer o'fpaper.pulpito'saidsurface with saidgrooves :substantially filled withip'ulp, holes in the cylinader wall alongzthe:bottoms of said grooves for the extraction 'ofwatr from the pulp, a press rollfhaving a smooth-cylindrical surfacecontacting the outersurface or the :pul-p deposited on said-cylinder and Fyieldingxmeans for, main- 5 tai nin gsai'd roll in contact with said pulp.

-6. Ina machine' ior molding corrugatedpaper ==b0ard the combination of a -cylind.erhaving a grooved outer surface; means for applying a-layer of pap-er pulp toisaid surface with said grooves *bubstdntially-filledwithtpulp, holes in theic'ylinder wall along the bottoms of said grooves for the e xtra'ction of :water from the pulp, a-press roll hav ing asmooth cylindrical surface contacting the outer surface :of the .1 pul deposited on K said cy-linder, I yielding means for maintaining said roll in contact with said 1 pulp, and: a-suction box within said cylinder underlying" said "roll.

7. Ina ma'chine for moldingcorrugated; paper board the combination of acylinderhavingla rooved surface, passagesj: through "the wallszor' saidcylincler along the bottoms of said grooves,

a pulp molding form for said cylinder of corrugated foraminous sheet material having portions extending into said grooves forming recesses to mold the ribs of the corrugated board, a flow box arranged for depositing paper pulp on said molding form, said-recess Portions of mesh screening and said mold form being of a different contour from the said grooves, thereby providing drainage spaces between the walls of said grooves and the foraminous sheet material, a press roll contacting the outer surface of the pulp deposited on said cylinder and yielding means for maintaining said roll in contact with said pulp.

, 8. In a machine for molding corrugated paper board the combination of a cylinder having grooves in its surface with ridges between the grooves, passages through the walls of said cylinder along the bottoms of said grooves, a pulp molding form of corrugated foraminous sheet material surrounding said cylinder, a flow box arranged for depositing paper pulp on said corrugated molding form, said sheet material having portions extending into the grooves of said cylinder forming recesses to mold the ribs of the corrugated board, and portions extending over the ridges of said cylinder to mold the intervening portions of the corrugated board, the recess portions of said molding form being of a different contour from the said grooves, thereby providing unimpeded passages between the walls of said grooves and the foraminous material of said molding form for the rapid drainage of water from said paper pulp to the passages in the bottoms of said grooves.

9. In a machine for molding corrugated paper board the combination of a cylinder having grooves in its surface with ridges between the grooves, passages through the walls of said cylinder along the bottoms of said grooves, a pulp molding form of corrugated foraminous sheet material surrounding said cylinder, a flow box arranged for depositing paper pulp on said corrugated molding form, said sheet material having portions extending into the grooves of said cylinder forming recesses to mold the ribs of the corrugated board, andportions extending over the ridges of said cylinder to mold the intervening portions of the corrugated board, the recess portions of said molding form contacting said grooves only along their top edges and along the mid portion of the bottom wall, thereby providing spaces between the walls of said grooves and the foraminous material of said molding form for the rapid drainage of water from said paper pulp to the passages in the bottoms'of said grooves.

10. In a machine for molding corrugated paper board the combination of a cylinder having grooves in its surface with ridges between the grooves, a pulp molding form of corrugated coarse superimposed fine mesh screening surrounding said cylinder, a flow box arranged for depositing paper pulp on said corrugated molding form, a suction box on the interior of said cylinder arranged to apply suction to the inner surface of the wall of said cylinder, passages through the walls of said cylinder along the bottoms of said grooves, said corrugated screening having portions extending into the grooves of said cylinder forming recesses to mold the ribs of the corrugated board, and portions extending over the ridges of said cylinder to mold the intervening portions of the corrugated board, the portions of said screening Within said grooves being of a different contour from the said grooves,

12 thereby providing unimpeded passages between the walls of said grooves and the screening for the drainage of water from said paper pulp to the passages in the bottoms of said grooves.

11. In a machine for molding corrugated paper board the combination of a cylinder having parallel grooves of rectangular cross section in its surface with parallel ridges between the grooves, passages through the walls of said cylinder along the bottoms of said grooves, a pulp molding form of corrugated coarse mesh screening and superimposed fine mesh screening surrounding said oylinder, a flow box arranged for depositing paper pulp on said corrugated molding form, said corrugated screening having portions extending into the grooves of said cylinder forming recesses to mold the ribs of the corrugated board, and portions extending over the ridges of said cylinder to mold the intervening portions of the corrugated board, the recess portions of said screening within said grooves being of semi-circular cross section contacting the mid portions of the bottoms of said grooves, thereby providing approximately triangular spaces between the walls of said grooves and said screening for the rap-id drainage of water from said paper pulp to the passages in the bottoms of said grooves.

12. In a machine for molding corrugated paper board the combination of a cylinder having grooves in its surface with ridges between the grooves, a pulp molding form of corrugated foraminous sheet material surrounding said cylinder, a flow box arranged for depositing paper pulp on said corrugated molding form, said sheet material having portions extending into the grooves of said cylinder forming recesses to mold the ribs of the corrugated board, and portions extending over the ridges of said cylinder to mold the intervening portions of the corrugated board, the recess portions of said molding form being of a different contour from the said grooves leaving spaces between the foraminous material and the walls of the grooves, the walls of the cylinder having unimpeded passages extending to said spaces for the rapid drainage of water from said paper pulp.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date Re. 22,842 Hill Feb. 18, 1947 183,444 Ball Oct. 17, 1876 1,377,765 Elling May 10, 1921 1,661,727 Koppelman et al Mar. 6, 1928 1,839,249 Nelson Jan. 5, 1932 2,000,085 Maginnis May 7, 1935 2,051,025 Bauer Aug. 18, 1936 2,079,667 Swift May 11, 1937 2,221,200 Perry Nov. 12, 1940 2,253,718 McKeage Aug. 26, 1941 2,321,574 Chaplin June 15, 1943 2,359,201 Chaplin et a1 Sept. 26, 1944 2,411,066 Stevens Nov. 12, 1946 2,515,113 Chaplin July 11, 1950 FOREIGN PATENTS Number Country Date 594,797 France Sept. 18, 1925 

